If she's gonna duet with a pop girl, I'd like it to be a huge name. Gaga used to write for her, they love each other and we all know their collab would be a worldwide 10 Million+ smash, so what are they waiting for.
Why would she even think of collaborating with Lady Gaga and Beyonce? Janet and Britney would be great but I doubt Janet have shown any appreciation for Britney. Did she? Britney always cite her as one of her major influences I think a Janet collab would be great.